He promises to supervise son and will notify authorities if his son tries to flee or disappears.

The father of a Dearborn Heights man suspected of supporting Islamic State extremists and planning to “shoot up” a Detroit church is seeking custody of his son while the 21-year-old faces a federal firearms charge. Khalil Abu-Rayyan is charged with illegally possessing a firearm while using a controlled substance. Prosecutors have not filed terrorism-related crimes against him.

On Monday, Rayyan Abo-Rayyan, identified as the father of Khalil Abu-Rayyan, submitted an affidavit and proposed agreement to the U.S. Attorney’s Office, asking for custody of his son and agreeing to supervise him according to the court’s orders while he awaits arraignment on a 10-year felony charge.

FBI has been investigating Abu-Rayyan since May “regarding increasingly violent threats he has made to others about committing acts of terror and martyrdom — including brutal acts against police officers, churchgoers and others — on behalf of the foreign terrorist organization Islamic State of Iraq and Levant,” according to a criminal complaint.

Abo-Rayyan says he will assure the appearance of his son at scheduled court hearings and will notify pretrial services if his son violated any condition of his release or if his son tries to flee or disappears.